Windows, transparent walls, and similar "thermal openings" in buildings have long been known to be a major source of heat loss from a building during cold periods and of heat gain during warm periods. The heating and cooling of a building has thus been known to require greater amounts of energy than would be necessary in the absence of windows or other "thermal openings". To the end that windows and the like can be configured to reduce such heat gains and losses, double-layered glass and similar insulative structures have been utilized. Further, it has come to be known that window coverings, such as shades, blinds, and curtains, provide at least some reduction in heat loss and/or heat gain relative to an otherwise exposed window.
As an example of a window shade structure of increased thermal efficiency relative to the substantially planar, relatively poor insulative window shading structures long known in the art, Luboshez, in U.S. Pat. No. 2,874,612, discloses a window shade having sections angularly disposed relative to each other, alternate sections being coated on at least one side with a heat-reflective material. The Luboshez shade structure is only one example of prior attempts to reduce heat gain, there having been similar attempts to reduce heat loss from an environmental space. The trapping of air between an essentially permanent, non-drawable window covering and a window surface has also been previously described in the art for reduction of heat flow through a window, seals being previously provided between such coverings and the frame holding the glass pane portion of the window to complete a "dead air" space between the covering and the window.
Other patents of interest include British Pat. Nos. 11,493 and 756,270 and U.S. Pat. Nos. 1,827,218; 1,937,342; 1,942,989; 2,170,877; 2,477,582; 2,551,736; 3,055,419; 3,256,931; 3,294,151; 3,294,152; 3,443,860; 3,465,806; 3,887,739; 3,899,326; 3,946,789 and 4,019,554.
While some of the window shades or coverings which have heretofore been proposed are capable, to some degree, of reducing heat loss or heat gain through a thermal opening, they are not entirely satisfactory particularly in reducing heat loss or gain by "convection". It is a matter of common experience that in addition to heat loss or heat gain through the window pane, considerable heat is often lost or gained by convection through the sides of the window frames. This convective heat loss or gain can frequently represent a significant amount of the total heat or energy.
Accordingly, it is an object of this invention to provide a shade structure for reducing the total heat loss or heat gain through a thermal opening, such as a window.
It is another object of this invention to provide a shade structure of unique configuration and design comprising a plurality of contiguous channels having "dead air" spaces, and a sealing structure extending along the window frame uniquely cooperating with the specially configured shade structure to insure against heat loss or gain, including convective heat loss or heat gain through the window.
It is also an object of this invention to provide a shade made of a generally flexible and resilient material comprising a plurality of contiguous channels of a generally honeycomb configuration having a plurality of air-entrapping cells, designed to cooperate with the sealing structure to minimize heat loss or gain, including convective heat loss or heat gain through the window.
The foregoing and other objects of this invention will become apparent from the following detailed description of the invention taken in conjunction with the accompanying drawings.